Hi All
On my '92 Super Duty, there are 2 main intake air hoses between the air cleaner and the throttle body. There is an interconnecting, plastic " H " fitting that also has a take off for the Idle Air Bypass solenoid. The main sections of the fitting neck down in a venturi shape to about 1 1/4" inside diameter each.
Can anyone tell me the purpose of these venturi shaped restricions?

Thanks,
Robert

 

Most say they are for intake noise reduction. Most of us cut the reduced area off (the venturi area), radius and smooth whats left and reinstall for more horsepower. Must have been an ex-Chevrolet engineer that got hired on at Ford to come up with that intake piece Deen

 

Hi Deen,
OK, that figures. I put a Banks "Power Pack " on my classs "A" motorhome. Part of the installations was to cut off the " venturis" and install a K+N filter in their modified filter housing. After installation I got a hellova lot of what I thought was intake noise. I had eliminated the cat, so there was more exhaust noise too, but that wasn't objectional. The intake noise was interesting. It's intensity varied depending on where you were in the front portion of the motorhome. It was worst in the driveres area, but would differ even by moving around in the seat. Wasn't too bad in the passenger's seat.
I'm going to stick them back on and see what happens.

Speaking of engineers. This brings up another question. The OEM engieers aren't usually too far off the mark when designing things for best compromises between performance, driveability, economy, and emmissions, within the normal expected driving RPMs, loads, and vehicle speeds. They design these " venturis " for silencing, and the exhaust system to do the same, yet some aftermarket company's would have the " venturi's " removed, and exhaust sytems as big as 3 1/2". Maybe necessary if you're turning 7500 RPM, but what about normal driving, 2000 to 3000, certainly no more than 4000 RPM?

Does anyone know how to calculate the actual intake and exhaust pipe size required for these conditions?

Thanks,
Robert

 

You for got one other area that's important that the engineers really have no control over...cost. The engineers could give us a much better overall product if the bean-counters didn't stop production because an item cost 10 cents more multiplied times 20,000-40,000 vehicles produced a year.
Anyway what size exhaust pipe does Gale Banks recommend in their 460 package? They Mfg. premier products and are probably number one for RV or heavy tow vehicle upgrades. If you call and they recommend 2.5" or 3" exhaust...then that's what I'd run. Deen

P.S. Robert, one other thing, OEM engineers figure items/ideas for the "masses" or the "average" driver. The people your rubbing shoulders here with in FTE_Truck are not your average driver, rather they are "enthusiasts" (sp?). We expect the best/most results from our vehicles which generaly leans more toward performance (more HP, or better mileage, or higher towing capacity)than the average generic vehicle...welcome to the group

 

Hi Deen
Looks like I'm in the right spot then. What began as simply as a fellow who twists wrenches for fun on a recreational vehicle has turned in to an obsession that's akin to a second job.
First, I added tha Banks system and an inductive discharge ignition to see if ( as advertised ), I could get more power and better economy. I did before and after tests, and documented the results, but that's a whole story in itself. Then I added a bunch of instrumentation to see what was going on.
The control strategy on the E4OD drove me nuts. I tried to find an aftermarket controller that would do what I wanted, with no success, so I built my own. That's another major story.
Now I figure I may be able to improve a few things with aftermarket engine management, so I'm in the process of installing a Haltech E6K to run the engine. Enthusiast? Yep, I guess you might call me that.
I went and had a look at my exhaust system. 3 inch to the muffler, 3 1/2 inch behind. Seems a bit of overkill for an engine turning 4000 RPM or less. I'm not an automotive engineer, but I suspect there is a fair amount of "cool" factor in there. Probably doesn't do any harm, but there is the issue of exhaust gas velocity to consider.
I wonder about removing the restriction in the intake as well. In the case of intake pipe size, it would make sense that bigger is better, but, at those engine speeds, just what is the percentage gain, the trade off being intake noise. Don't know the answer to that one.

Robert

 

Baumann Engineering builds controllers for the E4OD ( around $400.)and is a good place to reference to. They have a website at www.baumann engineering.com
One other problem you may run into is the E4OD is problamatic more so than the C-6 and is expensive to rebuild (upwards of $2,000 plus). Ford did a number of upgrades to repair the problems. To make the E4OD last you need to incorporate the mods up through 1995.
I can't tell you if a 3.5" exhaust is too large at low speeds...but my truck is used mainly for towing and the addition of headers, removing the intake restriction and installing a K&N filter really picked it up.
I picked up 10 MPH when towing 9,000 lbs up the long hills. I then put a MILD RV cam in (202in. 212ex.@ .050) and LOST a little low end but at highway speeds the truck flys (60-65 MPH) even through the mountains. My engine never sees more than 2700-2800 RPM unless I downshift.
The 429-460 big blocks are restricted on the exhaust side and most improvements are usually felt with the addition of headers, dual exhaust, or a split duration cam-shaft to improve the exhaust side scavenging. Good-luck in your experimenting! Deen

 

is there a "seat of pants" improvement by gutting the H-pipe

 

>is there a "seat of pants" improvement by gutting the H-pipe

No...an extra 5-10 HP (I'm guessing on increase)wouldn't normally be felt in a 5000 lb. vehicle. It's the combination of improvements that make the difference. Deen

 

Hi Deen,
Early on in my quest for an aftermarket controller I had contacted Baumann. Their unit didn't have manual control over the torque converter clutch, which I wanted. I talked to Karl Baumann about the possibility of modifying one to my spec, to which he seemed quite receptive, but after some time, he just wouldn't return my e mail, so I had to give up on him. Too bad, could have been a win win situation, I'd have got what I wanted, and his product could have been improved in the process. Besides, it sure would have been a lot easier than designing and building from scratch as I had to do.
Robert